खालील उतारा काळजीपूर्वक वाचा आणि त्यावर आधारित विचारलेल्या प्रश्नाचे (प्र. क्र. ४६ ते ५०) योग्य उत्तर निवडा:
अनादी काळापासून सुतारांना हे ठाऊक असावे की झाडांच्या खोडात गोलाकार कडी (वलये) असतात, ज्या लाकडात विशिष्ट रेषा आणि पोत (grain) निर्माण करतात. ॲरिस्टॉटलच्या सहकाऱ्यांनीही त्यांचा उल्लेख केला होता, परंतु झाड जसे वाढते तसे ते दरवर्षी एक नवीन कडे जोडते ही संकल्पना मांडणारी पहिली व्यक्ती लिओनार्डो दा विंची होती. आज आपल्याला समजते की जेव्हा वसंत ऋतू येतो आणि हिवाळ्यातील सुप्तावस्थेनंतर (dormancy) वनस्पती पुन्हा सजीव होतात, तेव्हा झाडाच्या सालीच्या आतील पेशींचे विभाजन सुरू होते. त्या मोठ्या, पातळ भिंतीच्या पेशी तयार करतात, ज्या फिकट रंगाच्या दिसतात आणि ज्यांना शास्त्रज्ञ 'अर्लीवूड' (early wood) म्हणतात. नंतरच्या काळात वाढ मंदावते आणि पेशी लहान व जाड भिंतींच्या बनतात. या 'लेटवूड' (latewood) मुळे झाडाच्या खोडात गडद रंगाची वलये तयार होतात. लेटवूड तयार झाल्यानंतर, हिवाळ्यासाठी झाड पुन्हा सुप्तावस्थेत जाते आणि हे चक्र दरवर्षी पुनरावृत्ती होते. परिणामी अनेक प्रजातींच्या खोडात एकाआड एक गडद आणि फिकट पट्ट्यांची मालिका तयार होते, ज्यातील प्रत्येक जोडी एका वर्षाच्या वाढीचे प्रतिनिधित्व करते. हे परस्परविरोधी पट्टे सुचिपर्णी (conifers) वृक्षांमध्ये सर्वाधिक स्पष्ट दिसतात; समशीतोष्ण पानझडी प्रजातींमध्ये ते तितके स्पष्ट नसतात आणि अनेक उष्णकटिबंधीय झाडांमध्ये तर ते पूर्णपणे अनुपस्थित असतात.
झाडे ही सजीव अभिलेखागार (living archives) आहेत, जी केवळ त्यांच्या वयाचीच नोंद ठेवत नाहीत तर ज्या ज्या वर्षी वलय तयार झाले त्या प्रत्येक वर्षातील पर्जन्यमान आणि तापमानाची नोंदही आपल्या रचनेत साठवून ठेवतात. या नोंदीमध्ये जंगलातील वणवे, अकाली पडणारे धुके/हिम आणि झाडाने पर्यावरणातून शोषून घेतलेले रासायनिक घटक यांचे ठसेही समाविष्ट असू शकतात. त्यामुळे जर आपल्याला त्यांची रहस्ये उलगडण्याचे ज्ञान असेल, तर झाड त्याच्या उगमापासून त्याच्या आसपास घडलेल्या घडामोडींबद्दल बरीच माहिती सांगू शकते. लेखी इतिहास उपलब्ध होण्यापूर्वी काय घडले हे झाडे सांगू शकतात. तसेच आपल्या भविष्याबद्दल सांगण्यासारखेही त्यांच्याकडे बरेच काही आहे. झाडांमध्ये साठवलेल्या भूतकाळातील हवामानाच्या नोंदी आपल्याला हवामान निर्माण करणाऱ्या नैसर्गिक शक्ती समजून घेण्यास मदत करतात, ज्यामुळे आपल्याला भविष्याचे नियोजन करणे शक्य होते.
गट 'A' मधील शब्दांच्या त्यांच्या गट 'B' मधील योग्य अर्थाशी जोड्या जुळवा.
Match the following words in A with their meanings in B.
AB
a. archivei. raining snowing
b. dormantii. trees shedding their leaves annually
c. precipitationiii. a place where historical documents or records are kept
d. deciduousiv. alive but not growing
EN
Read the following passage carefully and answer the question (Q. No. 46 to 50):
Carpenters from time immemorial must have known that tree trunks have rings, which give rise to the grain in a piece of wood. We find them mentioned by associates of Aristotle, but Leonardo da Vinci was the first person to suggest that as trees grow, they add a new ring every year. Today, we understand that when spring arrives and vegetation comes alive after the dormancy of winter, the cells just inside the bark of a tree start to divide. They produce large, thin-walled cells that we see as the light-coloured material scientists call earlywood. Later in the season, growth slows down and cells get smaller and thicker-walled. This so-called latewood looks darker and is what makes up the dark rings in a tree trunk. After latewood forms, the tree becomes dormant again for winter and the whole cycle repeats. The result is that many species carry in their trunks a series of alternating dark and light bands, each pair corresponding to a year's growth. These contrasting bands are most evident in conifers; distinctions between rings are not as pronounced in most temperate deciduous species and are absent in many tropical trees.
Trees are living archives, carrying within their structure a record not only of their age but also of precipitation and temperature for each year in which a ring was formed. The record might also include the marks of forest fires, early frosts and, incorporated into the wood itself, chemical elements the tree removed from its environment. Thus, if we only knew how to unlock its secrets, a tree could tell us a great deal about what was happening in its neighbourhood from the time of its beginning. Trees can tell us what was happening before written records became available. They also have a great deal to tell us about our future. The records of past climate that they contain can help us to understand the natural forces that produce our weather and this, in turn can help us plan. Match the following words in A with their meanings in B.
AB a. archivei. raining snowing b. dormantii. trees shedding their leaves annually c. precipitationiii. a place where historical documents or records are kept d. deciduousiv. alive but not growing
Trees are living archives, carrying within their structure a record not only of their age but also of precipitation and temperature for each year in which a ring was formed. The record might also include the marks of forest fires, early frosts and, incorporated into the wood itself, chemical elements the tree removed from its environment. Thus, if we only knew how to unlock its secrets, a tree could tell us a great deal about what was happening in its neighbourhood from the time of its beginning. Trees can tell us what was happening before written records became available. They also have a great deal to tell us about our future. The records of past climate that they contain can help us to understand the natural forces that produce our weather and this, in turn can help us plan. Match the following words in A with their meanings in B.
AB a. archivei. raining snowing b. dormantii. trees shedding their leaves annually c. precipitationiii. a place where historical documents or records are kept d. deciduousiv. alive but not growing